An application called “NetMeeting”, herein referred to as NM, is marketed by Microsoft Corporation for enabling two users to hold a data sharing session over a data communication between their two computers, each computer running a NM application. Before the present invention, one way of initiating a data sharing session would be for the initiating user to ask the other user for the network address of his computer, and upon receipt of that other network address the initiating user would then instruct the NM application running on his computer to make a data call to that other computer. Alternatively, users can arrange for their NM application to connect automatically upon launch to a selected one of several known directories, which creates an entry of the user's details for others to see in real time when they access that directory. Once connected to the directory, a user can select one of the entries, and his NM application can obtain the destination details for making a data call to the selected person (destination party). This requires that an initiating user knows which directory the desired destination party is using, and what name the destination party is using.